Development and usefulness of the gelatin-particle-agglutination test for titration of antibodies against diphtheria, pertussis and tetanus toxins

Development of a particle agglutination method with soluble virus receptor for identification of poliovirus

In the Global Polio Eradication Initiative, laboratory diagnosis plays a critical role by isolating and identifying poliovirus (PV) from the stool samples of patients with acute flaccid paralysis (AFP). In this study, we developed a particle agglutination (PA) method with a soluble human PV receptor (hPVR) in the form of an immunoadhesin (PVR-IgG2a) for the simple and rapid identification of PV. Sensitized gelatin particles with PVR-IgG2a showed specific agglutination with the culture fluid of PV-infected cells within 2 h of reaction in a one-step procedure. Detection limits for type 1, 2, and 3 PV(Sabin) strains were 1.5 x 10(6) 50% cell culture infectious doses (CCID(50)), 5.3 x 10(5) CCID(50), and 9.1 x 10(5) CCID(50), respectively. Wild-type PVs and PV isolates from acute flaccid paralysis cases examined were identified correctly with this PA method, except for some samples with a mixture of different serotypes of PVs, where a minor population of PV failed to be detected. These results suggest that this PA method is useful for the simple and rapid identification of PV, although the sensitivity was not high enough to detect a minor population of PV (<1/10 of the major population) among mixed PVs.

Collagen minipellet as a controlled release delivery system for tetanus and diphtheria toxoid

The use of biodegradable polymer matrices as a single-dose vaccine delivery system was investigated using tetanus toxoid (TT) and diphtheria toxoid (DT). BALB/c mice were immunized with TT or DT in different formulations including individual, in minipellet and aluminum hydroxide (alum), and the antibody responses were monitored for 48 weeks. Antigens entrapped in minipellet elicited higher antibody responses compared to those obtained with individual antigens and antigens adsorbed to alum and the antibody levels remained elevated over 48 weeks. In addition, minipellet formulations induced the same subclasses of antibodies induced by alum formulations. These results raise the possibility to obtain optimal and long-lasting immune responses by a single administration of minipellet formulations.